where 常用条件范例

where() public method

Sets the WHERE part of the query.

The method requires a $condition parameter, and optionally a $params parameter specifying the values to be bound to the query.

The $condition parameter should be either a string (e.g. 'id=1') or an array.

The $condition specified as an array can be in one of the following two formats:

• hash format: ['column1' => value1, 'column2' => value2, ...]
• operator format: [operator, operand1, operand2, ...]

A condition in hash format represents the following SQL expression in general: column1=value1 AND column2=value2 AND .... In case when a value is an array, an IN expression will be generated. And if a value is null, IS NULL will be used in the generated expression. Below are some examples:

• ['type' => 1, 'status' => 2] generates (type = 1) AND (status = 2).
• ['id' => [1, 2, 3], 'status' => 2] generates (id IN (1, 2, 3)) AND (status = 2).
• ['status' => null] generates status IS NULL.

A condition in operator format generates the SQL expression according to the specified operator, which can be one of the followings:

• and: the operands should be concatenated together using AND. For example, ['and', 'id=1', 'id=2'] will generate id=1 AND id=2. If an operand is an array, it will be converted into a string using the rules described here. For example, ['and', 'type=1', ['or', 'id=1', 'id=2']] will generate type=1 AND (id=1 OR id=2). The method will not do any quoting or escaping.

• or: similar to the and operator except that the operands are concatenated using OR. For example, ['or', ['type' => [7, 8, 9]], ['id' => [1, 2, 3]] will generate (type IN (7, 8, 9) OR (id IN (1, 2, 3))).

• not: this will take only one operand and build the negation of it by prefixing the query string with NOT. For example ['not', ['attribute' => null]] will result in the condition NOT (attribute IS NULL).

• between: operand 1 should be the column name, and operand 2 and 3 should be the starting and ending values of the range that the column is in. For example, ['between', 'id', 1, 10] will generate id BETWEEN 1 AND 10.

• not between: similar to between except the BETWEEN is replaced with NOT BETWEEN in the generated condition.

• in: operand 1 should be a column or DB expression, and operand 2 be an array representing the range of the values that the column or DB expression should be in. For example, ['in', 'id', [1, 2, 3]] will generate id IN (1, 2, 3). The method will properly quote the column name and escape values in the range.

  To create a composite IN condition you can use and array for the column name and value, where the values are indexed by the column name: ['in', ['id', 'name'], [['id' => 1, 'name' => 'foo'], ['id' => 2, 'name' => 'bar']] ].

  You may also specify a sub-query that is used to get the values for the IN-condition: ['in', 'user_id', (new Query())->select('id')->from('users')->where(['active' => 1])]

• not in: similar to the in operator except that IN is replaced with NOT IN in the generated condition.

• like: operand 1 should be a column or DB expression, and operand 2 be a string or an array representing the values that the column or DB expression should be like. For example, ['like', 'name', 'tester'] will generate name LIKE '%tester%'. When the value range is given as an array, multiple LIKE predicates will be generated and concatenated using AND. For example, ['like', 'name', ['test', 'sample']] will generate name LIKE '%test%' AND name LIKE '%sample%'. The method will properly quote the column name and escape special characters in the values. Sometimes, you may want to add the percentage characters to the matching value by yourself, you may supply a third operandfalse to do so. For example, ['like', 'name', '%tester', false] will generate name LIKE '%tester'.

• or like: similar to the like operator except that OR is used to concatenate the LIKE predicates when operand 2 is an array.

• not like: similar to the like operator except that LIKE is replaced with NOT LIKE in the generated condition.

• or not like: similar to the not like operator except that OR is used to concatenate the NOT LIKE predicates.

• exists: operand 1 is a query object that used to build an EXISTS condition. For example ['exists', (new Query())->select('id')->from('users')->where(['active' => 1])] will result in the following SQL expression: EXISTS (SELECT "id" FROM "users" WHERE "active"=1).

• not exists: similar to the exists operator except that EXISTS is replaced with NOT EXISTS in the generated condition.

• Additionally you can specify arbitrary operators as follows: A condition of ['>=', 'id', 10] will result in the following SQL expression: id >= 10.

  来源： <http://docset.velocity/Yii_(v2.0.4).docset/www.yiiframework.com/doc-2.0/yii-db-query.html#//apple_ref/clm/where%28%29>

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